What is the true state of a particle in superposition?

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Discussion Overview

The discussion revolves around the nature of superposition in quantum mechanics, specifically questioning whether it pertains to the particle itself or to our knowledge about the particle's state. Participants explore the implications of superposition on both physical properties and the concept of knowledge.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that superposition refers to the particle itself being in a superposition of states, while others argue it may relate to the uncertainty in our knowledge about the particle's state.
  • There is a suggestion that various properties of particles, such as quantum spin, can be in superposition, depending on the choice of operator.
  • One participant questions whether superposition is merely a matter of definition, using Schrödinger's cat as an example to illustrate the relationship between a system's state and our knowledge of it.
  • Another participant notes that interpretations of quantum mechanics, such as collapse and many-worlds, affect how one views the superposition of states and knowledge.
  • There is a challenge regarding the idea of "immaterial objects" being in superposition, with a focus on the importance of physical objects in physics.

Areas of Agreement / Disagreement

Participants express differing views on whether superposition applies to physical states or knowledge, and there is no consensus on the implications of superposition for immaterial concepts. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants highlight that the interpretation of superposition may depend on the choice of operator and the framework of quantum mechanics being applied, which introduces uncertainty in the definitions and implications discussed.

thermia
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TL;DR
Is it the partikel or the answer to the question?
When we say that a partikel - say a photon - is in superposition we assume the partikel itself is in superposition, but as I see it, the partikel is what it is. It is just that we don't know for the moment.
So, is the partikel itself in superposition, or is it the answer to the question about the position that is in superposition?
 
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thermia said:
Summary: Is it the partikel or the answer to the question?

So, is the partikel itself in superposition, or is it the answer to the question about the position that is in superposition?
It doesn't have to be. Various properties/states of particles can be in superposition. For instance, the property spin (quantum spin) can be in a superposition of states.
 
So is the superposition only a matter of definition? Schrödinger's cat's life is in superposition but also our knowledge about it's life is in superposition, or am I taking it too far?
 
DennisN said:
the property spin (quantum spin) can be in a superposition of states.

More precisely, it can be in a superposition of eigenstates of the spin operator in a particular direction. But whether or not a particular spin state is a superposition will depend on the direction you choose for the spin operator. Every spin state is an eigenstate of the spin operator in some direction, so every spin state is not a superposition for some choice of spin operator.

thermia said:
is the superposition only a matter of definition?

It's a matter of choice of operator. See above.

thermia said:
Schrödinger's cat's life is in superposition but also our knowledge about it's life is in superposition

This depends on which interpretation of QM you adopt. On a collapse interpretation, when you observe the cat, its state collapses to either "alive" or "dead". So even if the cat was in a superposition of alive and dead before you observed it, it isn't afterwards, so your knowledge of it is knowledge that it's alive or knowledge that it's dead, never a superposition of the two.

On a no collapse interpretation, such as many worlds, when you observe the cat, your state of knowledge (which is actually a physical state, the state of your brain) gets entangled with the state of the cat, so there are two "branches" or "worlds": one in which the cat is alive and you observe it to be alive, and one in which the cat is dead and you observe it to be dead. This is often described as a superposition, but "entangled" is a better term because the entanglement between the cat's state and your state of knowledge is independent of any choice of operator (whereas, as we saw above, whether or not a particular state of a quantum system is a superposition does depend on your choice of operator).
 
Thanks for your response.
As you may have got, my basic idea was if superposition refers only to physical objects or if immaterial objects such as "knowledge" also can be super positioned.
E.g. Your colleague opens the box and knows the state of the cat, but you still don't.
 
thermia said:
Your colleague opens the box and knows the state of the cat, but you still don't.

This isn't a case of quantum superposition. It's just straightforward classical ignorance--you don't know because you haven't interacted with the cat or your colleague so you have no information about their state.
 
So you say that immaterial objects can not be super positioned, or ... ?
 
thermia said:
So you say that immaterial objects can not be super positioned

What are "immaterial objects"? Physics isn't about "immaterial objects". It's about real, physical objects.
 
Sure
 
  • #11
thermia said:
Summary: Is it the partikel or the answer to the question?

When we say that a partikel - say a photon - is in superposition we assume the partikel itself is in superposition, but as I see it, the partikel is what it is. It is just that we don't know for the moment.
So, is the partikel itself in superposition, or is it the answer to the question about the position that is in superposition?
Both, because the question links both the state of the material and our knowledge about it. We usually say the state is undefined until a measurement is performed, you can infer the linkage, right.
 

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